On-chip calibration and control of optical phased arrays.

Optical phased arrays (OPAs) are important as they allow beam steering and scanning with no moving parts. As their channel count increases, the complexity of control and calibration becomes challenging. We propose an architecture and algorithm that provide rapid on-chip calibration and are scalable to arbitrary channel counts with significantly reduced chip area and reduced overall complexity compared to previously proposed approaches. The optimized phase shifter tuning algorithm - Deterministic Stochastic Gradient Descent (DSGD) - rapidly converges to the optimal state speeding up the digital-to-analog converter based control of large channel count OPAs.